1. The reason for lubrication
(1) Bearing lubricating oil is injected too much, exceeding two-thirds of the bearing cavity space. The heat transfer efficiency of the lubricating oil is not high, resulting in poor heat dissipation of the bearing.
(2) The bearing is short of oil. If the oil supply is too small, the oil supply is often interrupted, resulting in dry friction heating, and failure to deal with it in time will cause the bearing to burn out.
(3) The oil product has deteriorated. Failure to change the oil on time, oil seepage and emulsification, or poor airtightness will cause the oil to deteriorate if it enters the dust.
(4) The oil grade is wrong, and different oil products are mixed with each other.
2. Reasons for mechanical vibration
(1) Poor concentricity of the coupling causes vibration.
(2) Poor dynamic balance of flywheel, impeller and other types of rotating components or poor installation and alignment may cause vibration or uneven load.
(3) Too little rigidity of the bearing base causes vibration.
(4) Vibration caused by loose bolts.
Third, the reason for assembly
(1) The inner ring of the bearing with a withdrawal sleeve swells too tightly so that the radial clearance is too small, and the rolling element forms an excessive contact stress with the inner and outer rings.
(2) The outer ring of the bearing is pressed too tightly to deform it and cause excessive friction.
(3) The bearing installation is skewed.
(4) Friction and heating between the surrounding parts of the bearing and even smoke. Such as the friction between the shaft and the bearing box through the cover, the friction between the thrust plate and the shoe, the friction between the movable labyrinth and the fixed labyrinth.
(5) There is a thermal expansion gap at the end of the bearing end face of the floating end and the end face of the end cover, causing axial stress and heating.
(6) The V-belt assembly is too tight. The bearing directional load is too heavy, part of the rolling elements and the inner and outer rings have a large contact stress, the inner and outer rings are easy to change, and the raceways are easy to partly wear.
(7) Thrust bearings (usually used in pairs) do not leave a play gap between the outer ring and the rolling elements, but are tightly pressed on the rolling elements, resulting in excessive contact stress.
Four, environmental factors
(1) The system cooling water is too little or frequently interrupted, the indoor space is narrow and airtight, and the summer is hot and high temperature.
5. Reasons for operation
(1) Increase the load due to one-sided pursuit of output. Use bearing overload operation.
6. Bearing failure
(1) Cracks are formed in the inner and outer rings of the bearing, the cage is worn too much, the clearance exceeds the limit wear level, and the rolling elements are crossed, which have formed more serious defects.
Solution:
1. The reason for lubrication
(1) When cleaning and changing the oil, the bearing space is filled with grease, and one third of the bearing cavity is added. If the oil is usually refilled, one-third to two-thirds of the bearing cavity is the most appropriate.
(2) Replenish the oil on time and regularly check the integrity of the oil spray equipment. For example, the oil station should be cleaned or replaced on time to prevent blockage.
(3) The oil must be changed on time, the oil must be properly stored, and the bearing of the operating equipment must be sealed.
(4) Reasonable viscosity is the first element in selecting lubricating oil. Too low viscosity will lead to boundary lubrication or local boundary lubrication. Therefore, be sure to use reasonable oil.
2. Reasons for mechanical vibration
(1) Vibration causes the bearing to be subjected to abnormal extra load, and excessive stress causes the bearing to heat up. The coupling must be rigorously aligned.
(2) A dynamic balance test should be done, and strict alignment or adjustment should be made during installation to make the load of each bearing uniform.
(3) Strengthen and increase its rigidity.
(4) Tighten in accordance with the specified torque.
Third, the reason for assembly
(1) Measure the clearance while pushing forward during installation to ensure that the radial clearance of the bearing meets the technical requirements.
(2) Under normal circumstances, the outer ring of the bearing should not be pressed too tightly, because the rolling moment of the rolling elements is less than the sliding moment of the outer ring of the bearing.
(3) Bearing alignment.
(4) Re-adjust to reserve a suitable gap.
(5) Adjusting pads should be added to keep the gap to ensure that the shaft can promote the axial movement of the bearing during thermal expansion.
(6) Tension should be appropriate to reduce the orientation stress and friction torque, and increase the service life of the bearing.
(7) Add adjustment pads for adjustment, and reserve a small gap for transmission on both sides according to technical requirements.
Four, environmental factors
(1) Make sure that the cooling water is unblocked, increase the ventilation and heat dissipation capacity, and clean the bearings on time before the summer high temperature comes.
5. Reasons for operation
(1) The production must be reduced to the normal rated load.
6. Bearing failure
(1) The bearing is scrapped and the bearing must be replaced.
